Abstract:
U.S. Integrated Surface Irradiance Study (ISIS) Level 2 (SURFRAD) is digital data set DSI-9872, archived at the National Climatic Data Center (NCDC).ISIS is a continuation of earlier National Oceanic and Atmospheric Administration (NOAA) surface-based solar monitoring programs. ISIS provides basic surface radiation data with repeatability, ... consistency, and accuracy based on reference standards maintained at levels better than 1%. ISIS addresses questions of spatial distributions and time trends at sites selected to be regionally representative and long-term continuous records of observations. The Air Resources Laboratory (ARL) operates the NOAA national broadband solar radiation network, collecting data in both the visible and ultraviolet (UV-B) wavebands. ISIS operates at two levels: Level 1 stations are basic, monitoring incoming radiation only. Level 2 stations are more fully instrumented, focusing on surface radiation balance. Level 2 stations form the SURface RADiation Budget Network (SURFRAD) of stations.SURFRAD stations operate in the United States of America. Fifteen stations are planned. At this writing, NCDC has data in archive from 6 stations in climatologically diverse regions: Fort Peck, Montana; Boulder, Colorado;Bondville, Illinois; Goodwin Creek, Mississippi; Penn State, Pennsylvania; and Desert Rock, Nevada; from 1995 onward. Radiation measurements at SURFRAD stations cover the range of the electro-magnetic spectrum that affects the earth/atmosphere system. Global solar and its components are measured separately. Total downwelling (global) solar radiation is measured on the main platform by an upward looking broadband pyranometer. The direct component is monitored with a normal incidence pyrheliometer (or NIP) mounted on an automatic sun tracker, and the diffuse component is measured by a shaded pyranometer that rides on the solar tracker. Diffuse solar was not in the original suite of SURFRAD measurements. The shaded pyranometer was added in 1996 when a support platform with a shade arm mechanism was fitted to the trackers. A third pyranometer is mounted facing downward on a crossarm near the top of the 10-meter tower to measure solar radiation reflected from the surface. An upward looking pyrgeometer on the main platform measures long wave (thermal infrared) radiation emitted downward by clouds and other atmospheric constituents. Another pyrgeometer, mounted facing downward on the crossarm atop the tower, senses upwelling long wave radiation. These measurements of upwelling and downwelling in the solar and infrared wavebands constitute the complete surface radiation budget. Besides the surface radiation budget, other ancillary parameters are monitored. There are two instruments on the main platform that monitor wavebands of special interest. A UVB radiometer measures the degree of harmful ultraviolet radiation (290-320 nm) that evades the ozone layer and reaches the surface. Another instrument monitors the intensity of the waveband active in photosynthesis (400 to 700 nm). The final radiometer in the SURFRAD suite is the Multi-Filter Rotating Shadowband Radiometer (MFRSR) which measures both global and diffuse solar radiation in one broadband and six narrow bands of the solar spectrum. These are useful for obtaining aerosol loading information. Instruments for measuring wind speed and direction, air temperature, and relative humidity also reside at the top of the 10-meter tower. A barometer in the data logger box measures station pressure. The redundancy of three component solar measurements (global, direct and diffuse) provides a useful tool for quality control of the SURFRAD data. In addition, the sum of the diffuse and direct is actually a better measure of total solar than the global measurement alone because when the sun is near the horizon, a change in the cosine response of the global pyranometers sensor introduces errors in the global measurement. Level 2 major parameters are: global and direct beam irradiance, UV-B global irradiance, downwelling and upwelling thermal infrared, radiation active in photosynthesis, net solar (global-UPGBL), net infrared (IR-UPIR), net radiation (NETSOLAR+NETIR), temperature, relative humidity, wind speed and direction, station pressure, and solar zenith angle. The SURFRAD program has close ties with scientists at the University of Maryland; Pennsylvania State University; National Environmental Satellite, Data, and Information Services (NESDIS); the University Corporation for Atmospheric Research (UCAR) Office of Field Project Support; the GCIP project; the U.S. Department of Energy (DOE); and Unidata. SURFRAD is also part of the world-wide Baseline Surface Radiation Network (BSRN). Operationally, SURFRAD has the cooperation of the U.S. Department of Agriculture (USDA), the Fort Peck Tribes of Montana, Pennsylvania State University, and the Illinois State Water Survey.Observations from SURFRAD have been used for evaluating satellite-based estimates of surface radiation and for validating hydrology, weather prediction, and climate models.

Purpose:
To make a wide range of climatic data available to researchers and the public. SUPPLEMENTAL INFORMATION: data set CURRENTNESS REFERENCE: Ground Condition

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